1. Field of the Invention
The present invention relates to the field of watch cases, and more specifically, an electronic watch case.
2. Prior Art
Since the relatively recent advent of electronic digital-display wrist watches, several problems have continued to plague their construction, assembly and reliability. One difficulty has been in manufacturing a simple, yet reliable external switch by which electrical connections may be made within the watch mechanism. Another problem encountered in the prior art case construction has been in providing reliable electrical connections to batteries contained within the watch mechanism. Also, another difficulty in the prior art construction has been that the case back had to be installed before the watch would operate. Since the installation of the back, however, prevented access to timing adjustments within the case, the back would have to be removed for each adjustment and reinstalled to check the resulting timing accuracy.
One prior art attempt to provide an external switch for an electronic watch is described by Feurer, U.S. Pat. No. 3,783,607. Feurer utilizes a plunger which passes through a housing member in the watch case. The plunger moves longitudinally through the housing member, but the inward movement is opposed by a compression spring which surrounds a portion of the plunger. Thus, this method of construction requires not only sufficiently accurate machining of the case to provide for proper alignment and guidance of the plunger, but also the capability for utilizing a compression spring within the case wall. Due to the limited space available the spring must necessarily be small and fragile, and yet due to its application, must also withstand repeated compressions under varying forces. This repeated usage has the effect of stressing the spring, resulting in limited life and reliability.
One prior art attempt to provide electrical connections to batteries contained within the watch mechanism is described by Zurcher et al, U.S. Pat. No. 3,838,568. Zurcher utilizes battery hatch covers which are screwed into associated hatch openings in the back of the watch case. Disposed on the interior surface of the hatch covers are springs adapted to engage batteries in the watch mechanism. Seal rings are disposed between the hatch cover and the watch back so as to provide hermetic sealing. It can be seen from this brief description that relatively costly and complex machining is required for this construction. Not only must the small hatch covers be manufactured but corresponding screw threads must be provided on both the cover and the hole in the case back. In addition, springs and sealing rings must also be provided. Besides being complex, this construction requires a bulky back member so as to provide adequate surface area for screw threads to be disposed thereon, and watertight sealing is further compounded by two additional openings in the case.
In the present invention the problems of complex construction, lack of reliability and inconvenience of assembly, have been solved by utilizing a simple but effective inner-cover member in conjunction with a greatly simplified switch construction. The inner-cover, consisting of a stamped metallic member, not only provides reliable electrical connections to the watch batteries but completely replaces the switch return spring of the prior art. In addition, the inner-cover provides the necessary coupling of the watch batteries to electrical contacts on the watch mechanism upon actuation of the switch.